X-Ray Emitter and Method for Generating and Representing X-Ray Images

ABSTRACT

An X-ray emitter, particularly a dental X-ray apparatus, includes an X-ray source disposed in a housing, wherein the interior housing has an emission aperture and a diaphragm is provided which delimits the X-rays leaving the emission aperture to form a X-ray fan beam and is disposed at a distance from said emission aperture. In the space between the emission aperture and the diaphragm there are disposed radio-transparent means for deflecting light waves in the visible range, and in or on said housing there is provided an image detection system for the deflected light waves.

TECHNICAL FIELD

The invention relates to an X-ray emitter and a method for creating anddisplaying X-ray images.

DESCRIPTION OF THE RELATED ART

DE 3632878 A1 discloses an apparatus for positioning the head of apatient for the purpose of producing X-ray images, particularly a dentalpanoramic tomogram, by means of which apparatus the head of the patientis aligned with the display of the recorded silhouette of the patient'shead. A video camera and a video monitor are used for this purpose, thestored position being brought into register with the current position onthe video monitor. The video camera is adjusted in such a way that itsoptical axis coincides with that of the central ray of the X-rayemitter. This apparatus appears to be independent of the actual X-raydevice.

DE 10148412 A1 discloses a process and an apparatus for imaging the headregion of a patient, which apparatus is disclosed for both cephalometricX-ray and photographic images of objects to be X-rayed. The imagingposition of the X-ray emitter is adjusted according to the photographicimage. Both modes of imaging can be performed concurrently, wherein aphotographic camera is arranged in a mirrored arrangement laterally toan X-ray source. The beam path of the photographic camera is deflectedby the mirror so as to coincide with the X-ray beam.

It is an object of the invention to provide information, from a singlepanoramic rotation around an object to be X-rayed, concerning therelationship of the X-ray images and the visible surface of the object.

Another object is to provide a method by means of which not only anX-ray image is produced but also further information concerning theobject being examined is acquired and finally displayed.

SUMMARY AND OBJECTS OF THE INVENTION

This object is achieved with the X-ray emitter according to theinvention, which comprises an X-ray source disposed in a housingcomprising an emission aperture, a diaphragm being provided, which islocated at a distance from the emission aperture and which delimits theX-rays emitted through the emission aperture so as to form an X-ray fanbeam. Means for deflecting light waves in the visible range, which aretransparent to X-rays, are accommodated in the space between theemission aperture and the diaphragm.

The term “transparent to X-rays” means that the X-rays are notattenuated to such an extent that they become unsuitable for producingthe required image of the object to be examined.

Even in the case of tomographic imaging, it is possible, when using theX-ray emitter according to the invention, to produce such images of thevisible surface of the object to be X-rayed, as described above. Whencreating such images, the X-ray emitter must be positioned very close tothe object to be X-rayed, as opposed to cephalometric images. Thus thespace available for accommodating additional optical components as maybe necessary for imaging the visible surface of the object is verysmall. Accommodating these components, including the required deflectionmeans, in front of the primary diaphragm makes it unnecessary to modifythe imaging geometry.

Further advantageous embodiments are evident from the subclaims.

In an advantageous embodiment of the X-ray emitter, the deflection meansform a component of the emission aperture. This ensures that the spaceavailable is optimally utilized.

In another advantageous embodiment of the X-ray emitter, the deflectionmeans can be pivoted into the beam path of the X-rays. It is thenpossible to move the deflection means into the beam path only when it isdesired to create an image of the visible surface of the object to beX-rayed.

The deflection means advantageously consist of a vacuum-metalizedelement of plastics material showing low X-ray absorption. In this case,the deflection means can always remain in the beam path and a pivotedmechanism becomes unnecessary.

Furthermore, is has proven to be advantageous if the image recorder isaligned on a plane between the emission aperture and the diaphragm withits imaging direction extending at right angles to, and/or obliquely to,the direction of the X-ray fan beam. The image recorder can thus beaccommodated within the housing of the X-ray emitter.

Advantageously, in the X-ray emitter according to the invention, thegeometry of the surface image created by light in the range of visiblewavelengths is substantially the same as the geometry of the regionwhich is X-rayed. This substantially facilitates the formation of anassociation between the X-ray image and the visible surface of theobject being X-rayed.

It has proven to be particularly advantageous if the area to be X-rayedcoincides exactly with the video image delimited by the diaphragm. Anautomatic computer-aided overlap of the two images is thus madepossible.

BRIEF DESCRIPTION OF THE DRAWINGS

The process according to the invention is explained with reference tothe drawings, in which:

FIG. 1 shows a perspective view of an X-ray emitter having an integratedvideo camera together with the object to be examined,

FIG. 2 shows a cross section of the X-ray emitter illustrated in FIG. 1taken at the level of emission of the X-ray fan beam,

FIG. 3 shows an emission aperture with integrated deflection means,

FIGS. 4 and 5 show two different embodiments of the adjustabledeflection means.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION

The X-ray emitter 1 shown in FIG. 1 comprises a housing 2, in which theactual X-ray source 3 is disposed. The X-ray source 3 is shielded insuch a way that the X-ray is discharged only through an emissionaperture. The emission aperture 4 is designed to be transparent toX-rays for this purpose.

Regarded from the X-ray source 3, deflection means 5 in the form of amirror are located downstream of the emission aperture 4. Thesedeflection means 5 are likewise permeable to X-rays. However, thismirror 5 is substantially opaque to light waves in the opticallyperceivable range of wavelengths. The mirror 5 is arranged so as tocooperate with an image recording device 6 for light waves in thevisible range which is disposed in front of the emission aperture. TheX-ray fan beam 7, which is deflected by the mirror 5, is recorded bymeans of the camera 6. Said X-ray fan beam is directed towards theobject to be examined, here a patient 8, and illuminates the surfacepresent thereon. The beam path of the light reflected from the object 8to the image recording device 6 is illustrated by way of example bymeans of a central ray 9.

A cross section of the X-ray emitter 1 is shown in FIG. 2. An X-ray tube11 is located inside the housing, which X-ray tube is shielded from theenvironment, with the exception of the emission aperture 4, by aninternal housing 12, which is impermeable to X-rays. A diaphragm 13 isprovided between the emission aperture 4 and the object 8 beingexamined, which diaphragm delimits the X-ray beam, which is directedtowards the object 8 being examined, is produced by the X-ray tube 11,and is discharged through the emission aperture 4 to form a X-ray fanbeam.

An X-ray image, which is produced when the X-ray emitter and an sketchedimage detector 15 for the radiation passing through the object 8 rotatesaround the object 8 being X-rayed, shows structures, for example, bones,teeth and fillings existing under the surface of the object 8.

The surface of the object to be examined is videographed using thecamera 6, which is disposed away from the X-ray fan beam 14 of theX-rays and the beam path of which is aligned by the deflection means 5such that the beam path 7 with its central ray 9 substantially coincideswith the X-ray fan beam 14 and images the same area of the object 8.

At a pre-defined distance of a focus 16 from the diaphragm 13, there isusually sufficient installation space in the emission aperture 4 toaccommodate the deflection means 5 and the camera 6. A minimum distancebetween the focus and the diaphragm is expedient due to the finiteexpansion of the focus for preventing any disturbing influences of thepenumbra on the image detector 15.

In addition, the deflection means can be designed such that they can bemoved into and out of the beam path of the X-ray fan beam 14. This canbe effected either by means of a motor or manually, for example, using arod arrangement (not illustrated), which is accessible from outside thehousing 2. This is explained in detail below.

FIG. 3 shows an emission aperture 4, of which the outer side remote fromthe focus is in the form of deflection means for visible light. Suchmeans can take the form of, say, a mirror whose surface is designed as aserrated profile or a fractal lens, affording the possibility of exactfocusing.

The emission aperture itself is made of a material permeable to X-raysand the design of the surface located in the beam path affects thequality of the X-rays in the X-ray fan beam by not more than the extentthat may be tolerable for the creation of X-ray images.

FIGS. 4 and 5 show two different possible embodiments for adjustinginsertable deflection means.

The deflection means 5 are inserted along the guides 18, 19 laterallyinto the beam path by a spindle driven by a motor 17, as illustrated inFIG. 4.

In FIG. 5 a pivoted mechanism is provided for adjusting the deflectionmeans 5, which pivoted mechanism rotates the deflection means 5 fixed toa holder 20 about the rotation axis 21. This rotation can take placeeither horizontally or vertically depending on the design and the spaceavailable.

LIST OF REFERENCE NUMERALS

-   1 X-ray emitter-   2 Housing-   3 X-ray source-   4 Emission aperture-   5 Deflection means-   6 Camera-   7 Beam path-   8 Patient-   9 Central ray-   11 X-ray tube-   12 Interior housing-   13 Diaphragm-   14 X-ray fan beam (X-ray beam)-   15 Image detector-   16 Focus-   17 Motor-   18 Guide rail-   19 Guide rail-   20 Holder-   21 Rotation axis

1.-7. (canceled)
 8. An X-ray emitter, comprising an X-ray source (3)disposed in a housing (2), wherein an interior housing (12) has anemission aperture (4), a diaphragm (13) being provided which delimitsthe X-rays leaving said emission aperture (4) to form a X-ray fan beam(14) and is disposed at a distance from said emission aperture (4),wherein in the space between said emission aperture (4) and saiddiaphragm (13) there are disposed means (5) which are transparent toX-rays for deflecting light waves in the visible range, wherein in or onsaid housing (2) there is provided an image detection system (6) for thedeflected light waves, and wherein said deflecting means (5) form acomponent of said emission aperture (4).
 9. An X-ray emitter as definedin claim 8, which comprises part of a dental X-ray apparatus.
 10. AnX-ray emitter as defined in claim 8, wherein said deflecting means (5)consist of a vacuum-metalized element of plastics material showing lowX-ray absorption properties.
 11. An X-ray emitter as defined in claim 8,wherein said image detector (6) is oriented on a plane between saidemission aperture (4) and said diaphragm (13) in an imaging direction atright angles to, and/or obliquely, to the direction of said X-ray fanbeam (14).
 12. An X-ray emitter as defined in claim 8, wherein theimaging geometry of the surface registered by means of said imagedetection (6) for light in the range of visible wavelengthssubstantially coincides with the geometry of the X-rayed region of theobject being X-rayed.
 13. An X-ray emitter as defined in claim 8,wherein a region to be X-rayed coincides exactly with the imaginggeometry of the surface registered by means of said image detection (6)for light in the range of visible wavelengths.
 14. An X-ray emitter,comprising an X-ray source (3) disposed in a housing (2), wherein aninterior housing (12) has an emission aperture (4), a diaphragm (13)being provided which delimits the X-rays leaving said emission aperture(4) to form a X-ray fan beam (14) and is disposed at a distance fromsaid emission aperture (4), wherein in the space between said emissionaperture (4) and said diaphragm (13) there are disposed means (5) whichare transparent to X-rays for deflecting light waves in the visiblerange, wherein in or on said housing (2) there is provided an imagedetection system (6) for the deflected light waves, and wherein saiddeflecting means (5) are adapted to be moved into the optical path ofthe X-rays.
 15. An X-ray emitter as defined in claim 14, which comprisespart of a dental X-ray apparatus.
 16. An X-ray emitter as defined inclaim 14, wherein said deflecting means (5) consist of avacuum-metalized element of plastics material showing low X-rayabsorption properties.
 17. An X-ray emitter as defined in claim 14,wherein said image detector (6) is oriented on a plane between saidemission aperture (4) and said diaphragm (13) in an imaging direction atright angles to, and/or obliquely, to the direction of said X-ray fanbeam (14).
 18. An X-ray emitter as defined in claim 14, wherein theimaging geometry of the surface registered by means of said imagedetection (6) for light in the range of visible wavelengthssubstantially coincides with the geometry of the X-rayed region of theobject being X-rayed.
 19. An X-ray emitter as defined in claim 14,wherein a region to be X-rayed coincides exactly with the imaginggeometry of the surface registered by means of said image detection (6)for light in the range of visible wavelengths.